1. Field of the Invention
The present invention relates to an arrangement with a vacuum pump and a method of compensating a magnetic field produced by at least one vacuum pump component, e.g., a magnetic bearing and/or motor.
2. Description of the Prior Art
Since long ago turbomolecular pumps are used in vacuum technology for producing high and ultra-high vacuum. There, the vacuum production is based on a rotor having a plurality of blades offset relative to each other along the rotor axis and between which stator blades are arranged.
Usually, rotors are rotatably supported, in particular, in the turbomolecular pumps by at least one radially arranged magnetic bearing. Often, these magnetic bearings are supported axially by a second bearing, e.g., a ball bearing that insures an axial and radial stabilization.
Such a turbomolecular pump is disclosed, e.g., in DE 10 2010 052 660 A1.
A magnetic bearing usually is formed of several rings having a coil-shaped construction. The homogeneity of the rings is determined before their mounting in the turbomolecular pump and, according to practice, the rings are so tuned with respect to each other that inhomogeneity of separate rings is eliminated to a most possible extent.
However, often, a complete elimination of the inhomogeneity is not possible so that a resulting magnetic field is generated during operation of the turbomolecular pump.
In many applications which are known from practice, such magnetic fields do not cause any trouble because often they are relatively small.
However, when turbomolecular pumps are used in high sensitive apparatuses, e.g., for evacuation of test chambers of an electronic microscope, the magnetic interference field, which is generated, e.g., by magnetic bearings or a motor, can lead to a so-called dispersion, i.e., a certain unsharpness.
The object of the invention is to provide a turbomolecular pump in which a possible magnetic interference field of at least one component, e.g., a magnetic bearing and/or a motor is compensated, as well as a method of compensating a magnetic interference field of at least one component arranged in the turbomolecular pump, e.g., of magnetic bearing and/or motor, and which can be simply and economically implemented.